The interior of the Sun is divided into three regions, i.e. the core, radiative zone, and the convective zone.
The core is a gigantic reactor of radius 150 Mm ([1]}), where the nuclear fusion takes place and
the hydrogen (\(^1\) H) nuclei converted into helium (\(^4\) He) nuclei by proton–proton chain reaction and emit two particles: positron (e\(^+\) ) and neutrino (\(\nu \) ). Energy is released in the form of gamma rays ([2]}).
The proton–proton chain reaction is explained in Figure REF  and can be expressed as:
\(4^{1} H \longrightarrow ^{4}He + 2e^+ + 2\nu + 26.7 ~~MeV\) 
